Contact carrier strip



CONTACT CARRIER STRIP Filed March 17, 1966 CURRENT SOURCE INVENTOR. CHRISTIAN ADRIEN M,M, & COM

ATTORNEYS United States Patent U.S. Cl. 339176 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a thermoplastic contact carrier strip with a plurality of contacts embedded therein. The contact carrier strip is mated to a conductor carrying ribbon by means of welding electrodes which expose the conductors and contacts for electrical conduction by melting the thermoplastic.

This invention relates to a contact carrier strip and has as its objective the provision of a contact carrier strip which holds contacts in such a way that the contacts can be welded directly to the conductors of the ribbon cable.

The handling of a large number of contacts or connectors presents problems of movement and proper orientation. Towards this end it has been suggested to secure, mount or otherwise attach contacts to holding pieces or other retention devices, either temporarily or permanently. As the miniaturization of the electronics industry has proceeded, the size of contacts, terminals and other components has proportionately decreased, and thereby intensified the problem of handling the contacts.

The desirability of welding contacts and terminals to other conductors has added even more importance to the necessity to achieve handling of contacts and connectors. A novel welding technique is disclosed and claimed in co-pending application Ser. No. 317,617, filed Oct. 21, 1963, now abandoned, entitled Method of Securing Connector Terminals to a Ribbon Cable (inventerHerbert E. Ruehlemann).

In said application the terminals were positioned in the desired relationship with respect to the conductors of a ribbon cable prior to the initiation of the welding process. While this could be satisfactorily accomplished through the appropriate use of jigging machinery with larger contact surfaces, the inherent difiiculties in handling smaller contacts have made for a complicated industrial problem should it be desired to weld the smaller contacts to the conductor of a ribbon cable.

It is, therefore, an object of the present invention to provide a novel means for holding a plurality of contacts in desired relationship with respect to the conductors of a ribbon cable or other electrical device in order to permit the application of welding techniques.

Yet another object of the present invention is to provide a contact carrier strip which will hold small size contacts in desired relationship with respect to conductors of other devices, such as a ribbon cable in order to allow for the eflicient application of welding techniques.

Still another object of the present invention is to provide a contact carrier strip of relatively low cost which is simple in use and of high reliability.

The foregoing as well as other objects of the invention are achieved by providing a somewhat elongated plastic strip having contacts secured therein in precise relationship or spacing with respect to each other. The tail sections of the contact are sufliciently accessible to receive a welding current in order that the tail section may be welded to the conductor of a ribbon cable or other electrical device. In the preferred embodiment of the invention the tail section is incapsulated in the carrier strip which is of a thermoplastic material.

Thus, when heat is applied to the carrier strip, the thermoplastic insulation will be flowed away as a result 'of the combination effects of heat and pressure so that the tail section will be moved in actual contact with the conductor of a ribbon cable whose insulation has been similarly flowed away. Once mechanical contact has been established between the tail section and the ribbon cable conductor, a welding current can be applied in order to complete the connection.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a contact carrier strip of the present invention having female contacts secured therein;

FIG. 2 is a perspective view of one of the female contacts of FIG. 1;

FIG. 3 is a sectional view taken along the lines 33 of FIG. 1;

FIG. 4 is a perspective View of a male contact which can be secured Within a carrier strip in the manner of FIG. 1;

FIG. 5 is a plan view of the carrier strip of FIG. 1 with portions broken away for the sake of clarity; and

FIG. 6 is a sequential view illustrating the welding of a contact of the carrier strip of FIG. 1 to a conductor of a ribbon cable.

Referring now in greater detail to the various figures of the drawings wherein like reference characters refer to similar parts, there is shown at 10 in FIG. 1 a contact carrier strip embodying the present invention. The carrier strip 10 basically comprises thermoplastic holding portion '12 from which female contacts 14 extend. The contact carrier strip is preferably formed simultaneously or integrally so that the contacts 14 are embedded in the holding strip 12 upon discharge from the molding area. It is conceivable that other manufacturing techniques may be employed, such as separately forming the holding strip, heating the contacts and inserting the heating contacts under pressure so that they penetrate within the holding strip 12.

A typical female contact 14 is shown in perspective in FIG. 2 and a typical male contact 16 is shown in FIG. 4. The female and male contacts 14 and 16 indicated here illustrate the operation of the present invention. However, the present invention is in no way limited to the precise structure of the female and male contacts described herein. It will be readily apparent to those skilled in the art that contacts, both male and female or hermaphroditic may be utilized.

The female and male contacts 14 and 16 of FIGS. 2 and 4 are constructed generally along the lines of certain contacts disclosed and claimed in co-pending application Ser. No. 501,407, filed Oct. 22, 1965, entitled Cylindrical Connector Contact (inventorHerbert E. Ruehlemann), and the disclosure of said patent application is hereby incorporated in reference.

As generally shown in FIG. 2 the female contact 14 basically comprises a cylindrical mating section 18 and a relatively flat or uniplanar tail section 20. The contact 14 further includes cylindrical shoulder 22 from which the tail section 20 extends. A recess 24 is provided which separates shoulder 22 from mating section 18. As further shown in FIG. 2 the tail section 20 includes convex points 26 which strengthen the connection between the contacts 14 and the holding strip 12.

The disposition of the contacts 14 in the holding strip 12 is illustrated in FIG. 3 which indicates that the entire tail section 20, together with shoulder 22 and recess 24 is completely incapsulated within the holding strip 12 which terminates forwardly in edge 28 along a portion of the length of mating section 18. It will readily occur to those skilled in the art that the actual width of the holding strip 12 may be narrowed or may be broader, depending upon the needs of a particular situation.

It is conceivable that the holding strip 12 will encompass only middle portions of the contacts, thereby leaving substantial portions of the mating section and the tail section exposed. However, the holding strip 12 does have a protective function, since it prevents oxidation of the tail section 20 as well as lending some mechanical support.

The female contact further includes a central bore 30 which is adapted to receive the spring member 32 of the male contact 16, the details of which are shown in FIG. 4. The male contact 16 as well as the female contact 14 may be both comprised of maximum hardness beryllium copper, although softer materials may be used, depending upon the needs of a particular situation.

The male contact 16 basically comprises in addition to spring member 32 a body section 34 and cylindrical shoulder 36 from which tail section 38 extends. A recess 40 is provided which separates shoulder 36 from body setction 34. As further shown in FIG. 4 the tail section 38 includes convex points 42 which strengthen the connection between the contacts 16 and the holding strip 12.

The disposition of the contacts 16 in a holding strip is substantially identical to the FIGS. 1 and 3 disposition of female contacts 14 in the holding strip 12. Thus, the entire tail section 38, together with shoulder 36 and recess 40 may be completely incapsulated within the holding strip 12 that will terminate in a manner substantially identical to the showing of FIG. 3. As previously indicated, it will readily occur to those skilled in the art that the actual width of the holding strip 12 in conjunction with either female contacts 14 or male contacts 16 may be narrowed or may be broader depending upon the needs of a particular situation.

It is thus seen that the contact carrier strip of the present invention facilitates the handling of a plurality of female contacts 14 or male contacts 1 6. It is preferred that the female contacts or male contacts be integrally molded within the holding strip 12 at the time of the formation of the holding strip 12 as previously described. At times, it may be desirable to initially heat the contacts and then force them into a thermoplastic holding strip as described in Ruehlemann Patent No. 3,182,276.

Yet another advantage of the contact carrier strip of the present invention is to achieve the welding of a large number of contacts to the conductive members of a ribbon cable. This is shown in detail in FIG. 6. A ribbon cable is basically an elongated strip of plastic having conductive wires or members embedded or printed therein. In order to be usable with the present invention, the insulation of the ribbon cable should be thermoplastic or exhibit thermoplastic characteristics in the manner of a vinyl plastic or polyethylene.

A ribbon cable as known in the art is extremely thin and possesses a series of parallel conductive members which run lengthwise of the ribbon cable. However, the term ribbon cable is broad enough to include intersecting conductors or conductive matrices.

As shown in FIG. 6 the ribbon cable 44 comprises thermoplastic insulation 46 and at least one embedded conductor 48. As further shown in FIG. 6 the tail 20 of a female terminal as embedded in holding strip 12 is placed closely above the ribbon cable 44 in such a manner that the tail 20 is superimposed upon the conductor 40.

The details of a process involving the welding of a terminal to a conductor of a ribbon cable are disclosed in pending application Ser. No. 317,617, filed Oct. 21, 1963. ntitled Method of Securing Connector Terminals 4 to a Ribbon Cable (inventorHerbert E. Ruehlemann), and said details are herein incorporated in reference.

In order to carry out the welding process of FIG. 6, electrically heated electrodes 50 and 52 are employed in conjunction with current source 54 and leads 56 and 58. A condenser discharge circuit (not shown) as described in said application Ser. No. 317,617 may also be utilized in a switch or timer arrangement.

As shown in FIG. 6A, pressure is applied to the hot electrodes in the direction of the respective arrows in order to urge the hot electrodes 50 and 52 toward each other. Where the ribbon cable 44 is quite thin as shown in FIG. 6-A, the ribbon cable adjacent hot electrode 52 will immediately flow into a bulge 60. Thereafter, the insulation adjacent electrode 50 is melted away as shown in FIG. 6-B. Under continued heat and pressure as shown in FIG. 6-C, the insulation is flowed away not only from the top surface of contact tail 20, but also the heat passing from electrode 50 through tail section 20 as well as the heat emitted by lower electrode 52 passes through the ribbon cable and melts away the insulation adjacent the lower face of the tail 20.

It may be desirable to form the holding strip 12 from a thermoplastic material that will melt at a lower temperature than the thermoplastic material of the ribbon cable 44. In this way, the holding strip insulation will be more quickly flowed away than the ribbon cable insulation. Thus, the tail 20 will be rather quickly exposed to top electrode 50.

As shown in FIG. 6-C the combination of pressure and heat as applied by the electrodes 50 and 52 flows away the holding portion 12 and the ribbon cable insulation so that the tail section 20 is in actual contact with a conductor of the ribbon cable. A Welding current can now be passed through the actuation of switch means, either manually or through a timer in order to form weld 60 of FIG. 6-C. This process may be duplicated simultaneously or successively in order to weld a series of tail sections in the holding strip 12 to corresponding conductors of ribbon cable. It follows that the same process will apply when male contacts are present in the holding strip 12.

It is thus seen that the contact carrier strip of the present invention not only facilitates the handling of contacts, but is also well suited to expedite the holding of contacts to the conductors of a ribbon cable. The present invention is also well suited where the contacts are of small size. After the welding operation has been completed, a protective insulation coating or layer may be applied about the welded area for insulating as well as protective purposes.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed as the invention is:

1. A contact carrier strip comprising an elongated, relatively thin thermoplastic strip having a narrow edge; and a plurality of contacts secured in said strip in precise relationship to each other; said contacts including a mating section and a tail section, the mating sections of the contacts projecting beyond said narrow edge of the thermoplastic strip, and the tail sections of the contacts being encapsulated within said narrow edge by said thermoplastic strip whereby the tail sections of the contacts are protected by upper and lower thin thermoplastic layers.

2. The invention of claim 1 wherein said tail sections include convex points which strengthen the connection between'the thermoplastic strip and the tail sections.

3. The invention of claim 1 wherein said mating sections are female.

4. The invention of claim 1 wherein said mating sections are male.

5. The combination of a ribbon cable and a contact carrier strip; said ribbon being relatively flat and having a plurality of spaced conductors encapsulated side-by-side in thermoplastic insulation; said contact carrier strip comprising an elongated, relatively thin thermoplastic strip having a narrow edge, and having a plurality of contacts secured therein with a spacing matching that of said conductors; each contact having a mating section extending beyond said thermoplastic strip and a tail secion initially encapsulated by said thermoplastic strip and being welded to a different one of the plurality of conductors within the insulation of said ribbon cable, and portions of said thermoplastic strip being removed to achieve actual contact between the tail section of a contact and a conductor in said ribbon cable.

6. The invention of claim 5 wherein said tail section includes convex points which strengthen the connection between the thermoplastic strip and the tail section.

7. The invention of claim 5 wherein said mating section is female.

8. The invention of claim 5 wherein said mating section is male.

References Cited UNITED STATES PATENTS 3,016,512 1/1962 Borchardd 339-176 X 3,022,481 2/1962 Stepoway 339-176 3,129,995 4/1964 Brown 33997 3,155,809 11/1964 Griswold 33917 X 3,156,514 11/1964 Wing et a1 339l7 X 3,206,717 9/1965 Brown et al 339-1984 X MARVIN A. CHAMPION, Primary Examiner. JOHN R. MOSES, Assistant Examiner.

US. Cl. X.R. 339-47, 275 

